I'm on the economics job market! The largest insurers + PBMs in the United States also operate pharmacies. How does vertical integration between payers and pharmacies affect drug prices, insurance premiums, and consumer welfare? My #EconTwitter JMP 🧵: (1/15)

The running list of IO job market candidates for 2025-2026 is live! Fill this out to add your info: https://t.co/1hRIAD6IO1 Running list here:

I am super excited to share a new AI tool, Refine. Refine thoroughly studies research papers like a referee and finds issues with correctness, clarity, and consistency. In my own papers, it regularly catches problems that my coauthors and I missed. 1/

BREAKING NEWS The Royal Swedish Academy of Sciences has decided to award the 2025 Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel to Joel Mokyr, Philippe Aghion and Peter Howitt “for having explained innovation-driven economic growth” with one half to Mokyr

On Monday, October 13, the Nobel Prize in Economics goes to..... What's your prediction? #econtwitter

Using a field experiment, we studied how consumers valued Amazon brands and the extent of self-preferencing by Amazon. We found that Amazon brands bring benefits to consumers, even though they receive a modest prioritization in search rankings.

New evidence from a field experiment finds that Amazon brands generate positive benefits to consumers, despite having similar substitutes and receiving priority in search rankings, from Chiara Farronato, @AndreyFradkin, and @_amackay https://t.co/l0yJHxz5F2

The paper, joint with Chiara Farronato and @AndreyFradkin, is now available as an NBER working paper. @nberpubs link: https://t.co/ft5ET9YCLd SSRN:

Our findings suggest that policymakers and regulators should exercise caution when the assessing the role of vertically integrated products and services on platforms. Even corrections for self-preferencing can reduce consumer welfare, as we show in the paper.

A big reason why is that tastes vary, and some consumers have a preference for Amazon products. Amazon brands add about 5% to consumer surplus in the short run. This effect varies a lot across categories. We found the largest benefits in acid reducers and batteries.

We found: 1. Consumers select similar products when Amazon brands are not available 2. No evidence for changes in search behavior 3. No evidence for shifts to other retailers Despite these findings, we still found that consumers valued Amazon brands!

We also used structural modeling to quantify the benefits to consumers of Amazon products and simulate the potential price effects of having low-cost Amazon brands.

Using a custom browser extension we designed, we hid Amazon brands from a random subset of shoppers. We then looked at: - What products were selected in their absence - If consumer search behavior changed - If consumers went to other retail websites more often

Using a field experiment, we studied how consumers valued Amazon brands and the extent of self-preferencing by Amazon. We found that Amazon brands bring benefits to consumers, even though they receive a modest prioritization in search rankings.

New evidence shows stable total markups despite volatile manufacturer and retailer margins, highlighting shifting bargaining power along the supply chain, from Santiago Alvarez-Blaser, @albertocavallo, @_amackay, and @Paolo_Mengano https://t.co/bFrb61gs5Q

Little late, but worth sharing — @WSJ covered our study on the impact of access to full-day childcare services in CT w @john_eric Seth Zimmerman The finding that earnings rise and stay higher well beyond the period when kids are in childcare is striking to me, particularly

There is more in the paper, including how dynamics in bargaining translate to dynamic in pass-through. @nberpubs link here: https://t.co/zbMtPJWIWU Also available on SSRN: https://t.co/hgj1H31UcY Joint with @SEAlvarezBlaser @albertocavallo @Paolo_Mengano #econtwitter

The model helps explain the observed patterns. It allows us to interpret manufacturer-retailer profit shifts as changes in bargaining leverage. We evaluate the drivers of this leverage. The manufacturer gets a higher split with (e.g.) lower costs and greater market penetration.

Given the heterogeneity in product-level markups and the stability over time, we model pricing as occurring in two stages: 1. The manufacturer proposes downstream retail prices. 2. The manufacturer and retailers bargain over the wholesale price (and/or lump sum transfers).

We document supply chain markups in the US, the UK, Canada, and Mexico. We find several similarities, though the split of markups between manufacturers and retailers varies across countries.